Replaceable hammer tip

ABSTRACT

A replaceable hammer tip which is molded to incorporate as an integral part of its body the upper portion of an hexagonal head bolt of standard manufacture and a molded plastic stud lock. The stud lock has an hexagonal opening within which the head of the bolt is mounted to prevent rotation of the bolt with respect to the stud lock. The shank of the bolt extends through the center of the stud lock and protrudes from the lower edge of the tip for removable attachment to the hammer. The stud lock has a plurality of radially directed fins which engage the body of the tip to prevent rotation of the stud lock and a circular top which prevents vertical movement of the stud lock.

United States Patent [191 Carmien REPLACEABLE HAMMER TIP [75] Inventor:Joseph Allen Carmien, Sun Valley,

Calif.

[73] Assignee: Nupla Corporation, Sun Valley,

Calif.

22 Filed: Aug. 17, 1973 211 App]. No.1 389,234

[52] US. Cl. 145/29 A, 145/36 [51] Int. Cl B25d l/02 [58] Field ofSearch.... 145/29 A, 29 C, 29 R, 29 B, 145/29 D, 36

[56] References Cited UNITED STATES PATENTS 2,601,294 6/1952 Jahn et a1145/36 2,989,101 6/1961 Carmien 145/29 A 2,989,102 6/1961 Del Pesco etal 145/29 A 3,088,506 5/1963 Bianchini 145/36 [111 3,821,973 [451 July2,1974

Primary ExaminerAl Lawrence Smith Assistant ExaminerJ. T. ZatargaAttorney, Agent, or FirmRobert C. Comstock [57] ABSTRACT A replaceablehammer tip which is molded to incorporate as an integral part of itsbody the upper portion of an hexagonal head bolt of standard manufactureand a molded plastic stud lock. The stud lock has an hexagonal openingwithin which the head of the bolt is mounted to prevent rotation of thebolt with respect to the stud lock. The shank of the bolt extendsthrough the center of the stud lock and protrudes from the lower edge ofthe tip for removable attachment .to the hammer. The stud lock has aplurality of radially directed fins which engage the body of the tip toprevent rotation of the stud lock and a circular top which preventsvertical movement of the stud lock.

8 Claims, 5 Drawing Figures REPLACEABLE HAMMER TIP BACKGROUND OF THEINVENTION 1. Field of the Invention The invention relates to areplaceable hammer tip and more particularly to the attaching means forremovably securing the tip to a hammer.

2. Description of the Prior Art Prior to the present invention,replaceable hammer tips were provided with screw threaded attachingmeans-which comprised specially manufactured metal inserts. Because ofthe need of a large head area required to preclude rotation within theinsert top compared to the threaded stud diameter, the inserts wereexpensive and manufacturers of metal fastening devices were notinterested in making them. The special inserts have accordingly becomeincreasingly expensive and increasingly difficult to obtain. They alsorequire special metal forming molds which are relatively expensive tomake and operate, particularly in comparison with plastic molding.Further, the metal inserts have limitations as to the size andconfiguration which can be produced from the steel bar size required forthe threaded shank, hence less than the best anchor effects result. I

SUMMARY OF THE INVENTION The primary object of the present invention isto pro vide a replaceable hammer tip attaching means which does notrequire a specially manufactured metallic insert and which insteadutilizes standard fastening devices such as hexagonal head bolts whichare freely available on the market at an extremely low price.

Another object of the invention is to provide a stud lock for hammertips having means for holding a standard bolt against rotation withinthe stud lock and also having means for holding itself against rotationwith respect to the hammer tip.

A further object of the invention is to provide a replaceable hammer tipwhich is more economical to manufacture than those which are now in use.

The invention also comprises such other objects, advangages andcapabilities as will later more fully appear and which are inherentlypossessed by the invention.

While there is shown in the accompanying drawings a preferred embodimentof the invention, it should be understood that the same is susceptibleof modification I and change without departing from the spirit of theinvention.

DESCRIPTION OF THE DRAWINGS FIG. 1 is a side elevational view of areplaceable hammer tip in use, with the hammer shown in phantom lines;

FIG. 2 is a bottom plan view of the tip, taken on line 22 of FIG. 1;

FIG. 3 is an inverted sectional view of the tip taken on line 3-3 ofFIG. 1, with the bolt shown in elevation;

FIG. 4 is an inverted isometric view of the stud lock with the boltpartially inserted therein;

FIG. 5 is a bottom plan view of the stud lock.

DESCRIPTION OF THE PREFERRED EMBODIMENT A preferred embodiment which hasbeen selected to illustrate the invention comprises a replaceable hammertip having a body 10 which is customarily formed by injection molding ofvarious types of plastic materials, depending upon the particular tipcharacteristics which are desired. For example, vinyl may be used toprovide a soft, resilient, rubber-like tip. Nylon provides a tip whichis harder and more heat resistant. Commerce and industry require a widerange of hardnesses from 'as soft as flesh to as hard as brass.

Attaching means for removably securing the tip to the hammer areincorporated within the body 10 at the time the tip is molded. Suchattachment means preferably comprises a conventional standard bolt 11,which is preferably zinc plated. The bolt 11 has an hexagonal head 12and a screw threaded shank 13. Such bolts are commonly available on themarket at an extremely low price as articles of common manufactureavailable from a number of different competitive sources of supp y- As acoupling means between the bolt 11 and the tip body 10, a stud lock 14is utilized The stud lock 14 is preferably formed of relatively strongmolded plastic material such as fiberglass reinforced nylon. Other hard,heat resistant injection molding compounds may be used such as vinyl andothers known to those skilled in the art. The material used in formingthe stud lock 14 should be hard and strong so that the stud lock willnot bend or break in use, particularly in resisting rotation. Theparticular material selected depends on the character of the hammer tipmaterial in which it will be used. The material used must also be heatresistant because it is subjected to a second molding operation when itis incorporated within the body of the tip.

The stud lock 14 has a flat circular top 15, in the center of which anhexagonal opening 16 is provided. The opening 16 is formedcomplementarily to the shape and size of the hexagonal head 12 of theparticular bolt 11 with which it is used. The bottom of the bolt head 12fits against the bottom of the opening 16. Beneath the hexagonal opening16 is a concentric circular opening 17 which is dimensioned to receiveand fit around the upper portion of the shank 13 of the bolt 11. Thestud lock 14 is accordingly dimensioned to receive and securely fitaround the bolt 11 in such a manner that the bolt 11 cannot be rotatedwith respect to the stud lock 14.

Viewed from the outside, the stud lock 14 has a plurality (six in theembodiment shown) of spaced radially directed fins 18 which are disposeddirectly beneath the top 15 and which extend to its outer periphery. Theinner edges of the fins 18 terminate at a lower circular member 19 whichextends around the lower edge of the circular opening 17. Beneath thelower circular member 19 are three spaced downwardly directed arcuateskirts 20 which also engage the shank 13 of the bolt 11 and provideaccurate vertical positioning of the bolt 11 and stud lock 14 within thebody 10. The skirts 20 also control the length of exposed thread on theshank 13 to meet customer requirements.

The stud lock 14 includes an integral hexagonal portion 21 whichencloses the lower portion of the hexago- All of the portions of thestud lock 14 which have been described above are actually integralportions which are formed simultaneously in a single conventionalplastic injection molding operation.

In forming a replaceable hammer tip, a standard bolt 11 of suitable sizeand configuration is first mention in a previously molded stud lock 14,with the bolt head 12 disposed within the hexagonal opening 16 and thebolt shank 13 extending through the circular opening 17. Both are thenplaced in a plastic mold in which the body is molded around the studlock 14 and around the upper part of the bolt 11. The completed tipcomprises a body 10 having the lower screw threaded end of the boltshank 13 protruding from its lower edge as an attaching means forremovably securing the tip to a hammer. The remainder of the bolt 11 andthe entire stud lock 14-are completely enclosed within the tip body 10..

The hexagonal head 12 of the bolt 11 is securely held against rotationwithin the stud lock 14 by its engagement with the hexagonal opening 16.The fins 18 act to prevent any rotation of the stud lock 14 with respectto the body 10. The top of the stud lock 14 acts to prevent any verticalmovement of the stud lock 14 with respect to the body 10.

The result is that there is secure locking engagement between the bolt11 and body 10, whereby neither rotation nor vertical movement ispossible. The invention accordingly provides a means whereby a standardbolt may be used as an economical mounting means for a replaceablehammer tip.

While a bolt having an hexagonal head is shown and described, it will beobvious that any other type of irregular head configuration may be used.It will also be obvious that the particular shape of the tip itselfmakes no difference in the operation of the invention.

I claim:

1. A replaceable molded hammer tip comprising a bolt of standardmanufacture having a head of irregular configuration and an externallyscrew threaded circular shank, a stud lock having an irregular openingin the upper portion thereof formed complementarily to and fittingaround the head of said bolt, said stud lock having a circular openingthrough which the shank of said bolt extends, said hammer tip beingmolded around said stud lock and around the upper portion of said boltto provide a tip having a body with the lower portion of the screwthreaded shank protruding therefrom, said stud lock having meansengaging the body of said tip to prevent rotational movement of saidstud lock with respect to the body of said tip.

' 2. The structure described in claim 1, said bolt having an hexagonalhead and said stud lock having an hexagonal opening.

3. The structure described in claim 2, said engaging means between saidstud lock and the body of said tip comprising a plurality of radiallydirected fins formed as an integral part of said stud lock.

4. The structure described in claim 3, said stud lock having means forpreventing vertical movement of said stud lock with respect to saidbody.

5. The structure described in claim 4, said stud lock having a circulartop, said fins being disposed beneath said top, said stud lock havingopen spaces between said fins and beneath said top, whereby the lowerend of said top forms a locking engagement with the body of said tip toprevent downward vertical movement of said stud lock with respect to thebody of said tip.

6. The structure described in claim 5, the head of said bolt and theentire stud lock being enclosed within the body of said tip so that onlythe lower end of said screw threaded shank protrudes from said tip.

7. The structure described in claim 6, said stud lock being formed offiberglass reinforced nylon.

8. The structure described in claim 7, said bolt being zinc plated.

1. A replaceable molded hammer tip comprising a bolt of standardmanufacture having a head of irregular configuration and an externallyscrew threaded circular shank, a stud lock having an irregular openingin the upper portion thereof formed complementarily to and fittingaround the head of said bolt, said stud lock having a circular openingthrough which the shank of said bolt extends, said hammer tip beingmolded around said stud lock and around the upper portion of said boltto provide a tip having a body with the lower portion of the screwthreaded shank protruding therefrom, said stud lock having meansengaging the body of said tip to prevent rotational movement of saidstud lock with respect to the body of said tip.
 2. The structuredescribed in claim 1, said bolt having an hexagonal head and said studlock having an hexagonal opening.
 3. The structure described in claim 2,said engaging means between said stud lock and the body of said tipcomprising a plurality of radially directed fins formed as an integralpart of said stud lock.
 4. The structure described in claim 3, said studlock having means for preventing vertical movement of said stud lockwith respect to said body.
 5. The structure described in claim 4, saidstud lock having a circular top, said fins being disposed beneath saidtop, said stud lock having open spaces between said fins and beneathsaid top, whereby the lower end of said top forms a locking engagementwith the body of said tip to prevent downward vertical movement of saidstud lock with respect to the body of said tip.
 6. The structuredescribed in claim 5, the head of said bolt and the entire stud lockbeing enclosed within the body of said tip so that only the lower end ofsaid screw threaded shank protrudes from said tip.
 7. The structuredescribed in claim 6, said stud lock being formed of fiberglassreinforced nylon.
 8. The structure described in claim 7, said bolt beingzinc plated.